1. Field of the Invention
The present invention is related to an undercoat agent which is used for phase separating a layer including a block copolymer having a plurality of blocks bonded formed on a substrate, and a method of forming a pattern of a layer containing a block copolymer by using the undercoating agent.
Priority is claimed on Japanese Patent Application No. 2012-057815, filed Mar. 14, 2012, the content of which is incorporated herein by reference.
2. Description of Related Art
In recent years, the continued miniaturization of large scale integrated circuits (LSI) has lead to demands for techniques capable of processing ever finer structures. In response to these demands, testing has commenced into the formation of finer patterns using phase separation structures that are formed by the self-assembly of block copolymers containing mutually immiscible blocks bonded together.
In order to utilize this type of block copolymer phase separation, a self-assembled nanostructure formed by microphase separation must be formed within only a specific region, and must be oriented in a desired direction. In order to achieve this positional control and orientation control, methods such as graphoepitaxy, which controls the phase separation pattern using a guide pattern, and chemical epitaxy, which controls the phase separation pattern based on differences in the chemical state of the substrate, have been proposed (for example, see Non-Patent Document 1).
One method that has been proposed for achieving favorable phase separation of a block copolymer, thus enabling formation of a very fine pattern, is a method in which a neutral layer having a surface free energy that is between the surface free energy values of two block chains is formed on the substrate, so that the surface on the substrate with which the block copolymer makes contact has a surface free energy value that is between the surface free energy values of the two block chains (for example, see Patent Document 1).